1. Promotion of DAT test prep materials is not allowed.
    Dismiss Notice
  2. Guest, be sure to check out How To Get Into Dental School, our free downloadable PDF with step-by-step details for dental school applicants!
    Dismiss Notice
  3. New SDN Article! Q&A with Physician Writer Sandeep Jauhar And a review of Dr. Jauhar's new book, Heart: A History.
    Dismiss Notice
  4. Download free Tapatalk for iPhone or Tapatalk for Android for your phone and follow the SDN forums with push notifications.
    Dismiss Notice
DAT Test Prep Material Discussion Free Dental Admissions Guide Article: Jauhar Tapatalk

Emprical Formula

Discussion in 'DAT Discussions' started by Dencology, May 28, 2008.

Previous Thread Next Thread
Loading...
  1. Dencology

    Dencology
    2+ Year Member

    Joined:
    Mar 7, 2008
    Messages:
    396
    Likes Received:
    0
    Status:
    Pre-Dental
    A compound consist of carbon, hydrogen, and oxygen is known by quantitative analysis to have 55.2% oxygen and 3.4% hydrogen by mass. what is the empirical formula?
    guys, if the mass of Carbon is not given how do we do this? i know that some people just do this calculation by looking at the choices. Like the amount of Oxygen is almost half the amount of the compound therefore, carbon needs to be a little less or almost the same amount as oxygen.

    a. CHO
    b. CH2O
    c. CH3O
    d. C2H6O2
    e.CH4

    the answer is A. but how can we do this without calculation so we can speed up.
     
    #1 Dencology, May 28, 2008
    2. Note: SDN Members do not see this ad.

  2. Zerconia2921

    Zerconia2921 Bring your A-game!
    2+ Year Member

    Joined:
    Mar 24, 2008
    Messages:
    207
    Likes Received:
    0
    Status:
    Pre-Pharmacy
    If the carbon isnt given it can stll be calculated because the percent is out of 100. We have 55.2% + 3.5% = 58.7% So 100%-58.7%=41.3% of Carbon

    oxygen .552/16g/mol = .03mol, hyrogen .035/1g/mol = .03mol, carbon .413/12g/mol = .03mol

    0.03mols/0.03mols = 1

    CHO answer A
     
    #2 Zerconia2921, May 28, 2008
  3. Dencology

    Dencology
    2+ Year Member

    Joined:
    Mar 7, 2008
    Messages:
    396
    Likes Received:
    0
    Status:
    Pre-Dental
    thanks.
     
    #3 Dencology, May 28, 2008
Previous Thread Next Thread
Loading...
(You must log in or sign up to post here.)

Share This Page